Fluoxetine and sertraline dosages in major depression

In a retrospective study, we sought to determine medication dosages usually prescribed to obtain euthymia in 59 outpatients with a diagnosis of major depression treated with fluoxetine or sertraline. Charts of veterans admitted to the outpatient mental health clinic at the West Los Angeles Veterans Hospital with a diagnosis of major depression and treated with either fluoxetine or sertraline were reviewed. Progress notes were analyzed for a 6-month time period after the initiation of the medication treatment, and improvement was rated by a physician blind to the drug used for treatment. No significant differences were found in overall response rates between the fluoxetine (81% responders) and sertraline (76% responders) groups. Eighty-one percent of the fluoxetine responders compared to 32% of sertraline responders were at the manufacturer's recommended starting dose (MRSD) at the time of clinical response. One-third of patients receiving sertraline were started on or rapidly titrated to more than 50 mg/day. When only those patients receiving an adequate trial of sertraline at 50 mg were considered, 47% required a dose increase to achieve a remission. These data suggest that 50 mg of sertraline may be inadequate for some patients to achieve a resolution of symptoms of major depression and that many clinicians currently prescribe in a manner suggesting that they believe the MRSD is a suboptimal dosage.

Clinical pharmacology studies in patients with renal impairment: past experience and regulatory perspectives

The objective of this report is to provide a regulatory perspective on the quality of pharmacokinetic studies in renal impairment (RI) studies submitted in support of new drug applications (NDAs) or supplements to NDAs (sNDAs) submitted to the Food and Drug Administration (FDA). Fifty-one NDA and 20 sNDA submissions reviewed between 1996 and 1997 by the Office of Clinical Pharmacology and Biopharmaceutics were evaluated for the following: (1) whether an RI study was conducted; (2) contribution of the renal clearance to the overall clearance in subjects without renal impairment; (3) degree of plasma protein binding (%PB) in subjects without renal impairment; (4) dose proportionality of single and multiple doses; (5) study design, including dosing regimen; (6) definition of renal impairment; (7) stratification of renal functions; (8) number of subjects/group; (9) data analysis and interpretation; and (10) impact on labeling. Results of the analysis indicated that 67% of the NDAs and 30% of supplemental NDAs contained RI-studies (34/51 for NDAs and 6/20 for sNDAs). No obvious differences in the pharmacokinetic characteristics (e.g., percentage excreted unchanged in urine and %PB) were observed between drugs for which RI studies were conducted versus those not conducted. Most studies conducted were designed as single dose (70%). Seventy-five percent of the studies used doses within the therapeutic dosage range of the drug. The measured 24-hour creatinine clearance was most often used to assess the renal function. Stratification of renal function ranged from one to five groups, with 6 to 8 subjects enrolled per group. In most studies conducted (38/40), data were analyzed by point estimate using ANOVA. Results of RI studies were adequately reflected in the labeling. The survey reveals that RI study design can be improved for regulatory review purposes. In part based on this analysis, the FDA has prepared a guidance that provides recommendations on the design, analysis, and impact on dosing and labeling for RI studies to include recommendations on when RI studies do not need to be performed. The guidance proposes an equivalence approach with confidence intervals, as opposed to a point estimate approach, to assess the impact of RI on systemic exposure measures.

Barriers to participation in randomised controlled trials: a systematic review

METHOD

A systematic review of three bibliographic databases from 1986 to 1996 identified 78 papers reporting barriers to recruitment of clinicians and patients to randomised controlled trials.

RESULTS

Clinician barriers included: time constraints, lack of staff and training, worry about the impact on the doctor-patient relationship, concern for patients, loss of professional autonomy, difficulty with the consent procedure, lack of rewards and recognition, and an insufficiently interesting question. Patient barriers included: additional demands of the trial, patient preferences, worry caused by uncertainty, and concerns about information and consent.

CONCLUSIONS

To overcome barriers to clinician recruitment, the trial should address an important research question and the protocol and data collection should be as straightforward as possible. The demands on clinicians and patients should be kept to a minimum. Dedicated research staff may be required to support clinical staff and patients. The recruitment aspects of a randomised controlled trial should be carefully planned and piloted. Further work is needed to quantify the extent of problems associated with clinician and patient participation, and proper evaluation is required of strategies to overcome barriers.

The public vs private debate: separating facts from values

The choice between public and private emergency ambulance services is generally based on histological experience within the community. No empirical evidence exists that supports an argument that either public or private emergency ambulance services are better, per se. On a macro level, this debate is based on the question of the role of government and the role of the marketplace in the delivery of public services and medical care, and the comparative efficiencies of public and private organizations. On a micro or community level, these philosophical concerns are supplemented with issues relating to protection of individual jobs and investments, upholding of community tradition, and maintenance of existing relationships. Other specific values that are considered include the role of profit and equity--fairness of coverage. A rational choice would be based on consideration of efficiency and effectiveness. The effectiveness of an emergency medical services system is primarily based on its ability to provide patients with the level of care that they need within a clinically appropriate time. Efficiency is the ratio between inputs and outputs. One factor that can increase efficiency is the availability of excess production capacity that can be used to provide emergency ambulance service, with a low marginal cost of adding this to the other functions. A rational model is intended to change the level of the debate to one that is less based on values, but it is impossible for a community to select an ambulance provider in a value-free environment.

A systematic review of the skeletal effects of estrogen therapy in postmenopausal women. I. An assessment of the quality of randomized trials published between 1977 and 1995

PURPOSE

To examine the quality of published randomized controlled trials of the effects of estrogen treatment on fracture risk and measures of bone mass.

DATA SOURCES

Articles on estrogen treatment for osteoporosis published between 1977 and 1995 were identified by searching Medline and Excerpta Medica databases and bibliographies of original papers and published reviews.

STUDY SELECTION

Studies selected were randomized controlled trials of the efficacy of estrogens in preventing loss of bone mass or fractures in postmenopausal women.

DATA EXTRACTION

Data extraction and quality assessment were performed in duplicate, with assistance of a manual. Raters were blinded as to authors and their affiliations and the publication details.

RESULTS

Of 99 eligible randomized controlled trials published between 1977 and 1995, eight included no extractable data, and 23 contained results that were published in duplicate. Total quality scores increased over time, but this was accounted for by improvements only in the measurement technologies used to estimate bone mineral content or density. There was no improvement in the quality of randomization methods, the extent to which withdrawals were accounted for, or in the baseline comparability of treated and control patients. Neither sample sizes nor durations of follow-up increased over time.

CONCLUSIONS

This body of literature fails to address whether estrogen therapy reduces fracture rates, and does not allow for comparison of the effects of different active therapies on change in bone density. Although there were improvements in the techniques for estimating bone mass and delivering estrogen treatment, the studies published in the 1990s were no more informative for making clinical or policy decisions than those published in the 1970s.

A systematic review of the skeletal effects of estrogen therapy in postmenopausal women. II. An assessment of treatment effects

PURPOSE

To combine the results of randomized controlled trials to provide overall estimates of the effect of estrogen treatment on fracture rates and measures of bone mass.

DATA SOURCES

Articles on estrogen treatment for osteoporosis published between 1977 and 1995 were identified.

STUDY SELECTION

Studies selected were randomized controlled trials of the efficacy of estrogens in preventing loss of bone mass or fractures in postmenopausal women.

DATA EXTRACTION

Data extraction and quality assessment were performed in duplicate, with assistance of a manual. Raters were blinded as to authors and their affiliations and the publication details. With estimates of bone mass, the treatment effect size was defined as the difference in the mean annual change in bone mass between the treatment and control groups divided by the pooled standard deviation for change. In the case of fractures, efficacy was measured as the reduction in the numbers of individuals experiencing new fractures with treatment. Effect sizes were pooled using the random effects model.

RESULTS

Thirty-seven studies met the criteria for inclusion in the systematic review. Only one small secondary prevention trial contained evaluable data on vertebral fractures. This study found a fracture relative risk of 0.63 (95% confidence interval, CI 0.28-1.43) with estrogen treatment. There was more information on the effects of treatment on bone mass. Overall effect sizes ranged between 0.5 and 2.5 standard deviation (SD) units for change. A dose-response relationship was apparent but high doses of estrogens were not associated with effect sizes greater than those observed with recommended doses. There was no significant difference in efficacy between transdermal and oral administration of estrogens. Pooling of paired data from secondary prevention studies indicated that treatment effect sizes were smaller at the hip (0.92, 95% CI 0.3-1.5 SD units) than at the spine (2.1, 95% CI 0.9-3.3 SD units). No significant effects of co-intervention with calcium, progestogens or androgens were seen, although an additive effect of higher doses of calcium could not be ruled out.

CONCLUSIONS

Clear-cut effects of estrogens in attenuating the postmenopausal decline in estimated bone mass were apparent in this literature. However, the trials were short-term and provide inadequate evidence on the effects of treatment on fracture risk.

Regulation of alpha 2,3-sialyltransferase expression correlates with conversion of peanut agglutinin (PNA)+ to PNA- phenotype in developing thymocytes

Staining of thymus tissue with the plant lectin peanut agglutinin (PNA) is a classic technique for defining the cortical (PNA+) and medullary (PNA-) regions of this tissue. These two regions are primarily composed of immature and mature thymocytes, respectively. Conversion of the PNA+ to the PNA- phenotype has been attributed to masking of the cell surface carbohydrate receptors of PNA by sialic acid during the intrathymic maturation of these cells. We present evidence that the regulated expression of a single glycosyltransferase, a Gal beta 1,3GalNAc alpha 2,3-sialyltransferase, can account for this glycosylation change. This enzyme sialylates the preferred ligand of PNA, Gal beta 1,3GalNAc, forming the sequence NeuAc alpha 2,3Gal beta 1,3GalNAc, thus masking PNA binding sites. Expression of the enzyme is inversely proportional to expression of the PNA receptor, as evidenced by analysis of T-lymphoblastoid cell lines and by in situ hybridization experiments in human thymic tissue.

Cloning and expression of the Gal beta 1, 3GalNAc alpha 2,3-sialyltransferase

Sequence information obtained by NH2-terminal sequence analysis of two molecular weight forms (45 and 48 kDa) of the porcine Gal beta 1,3GalNAc alpha 2,3-sialyltransferase was used to clone a full-length cDNA of the enzyme. The cDNA sequence revealed an open reading frame coding for 343 amino acids and a putative domain structure consisting of a short NH2-terminal cytoplasmic domain, a signal-anchor sequence, and a large COOH-terminal catalytic domain. This domain structure was confirmed by construction of a recombinant sialyltransferase in which the cytoplasmic domain and signal-anchor sequence of the enzyme was replaced with the cDNA of insulin signal sequence. Expression of the resulting construct in COS-1 cells produced an active sialyltransferase which was secreted into the medium in soluble form. Comparison of the cDNA sequence of the sialyltransferase with GenBank produced no significant homologies except with the previously described Gal beta 1,4GlcNAc alpha 2,6-sialyltransferase. Although the cDNA sequences of these two enzymes were largely nonhomologous, there was a 45-amino acid sequence which exhibited 65% identity. This observation suggests that the two sialyltransferases were derived, in part, from a common gene.

A transcriptional repressor of c-myc

In murine plasmacytomas there is deregulated transcription of a translocated c-myc allele and undetectable transcription of the normal, unrearranged c-myc allele. Deregulated c-myc transcription probably contributes to the transformed phenotype of the tumour cells, whereas repression of the normal allele probably reflects the normal turn-off of c-myc in non-dividing plasma cells. We previously identified a plasmacytoma-specific protein which binds to the c-myc promoter region 290 base pairs 5' of the P1 transcription start site. This plasmacytoma repressor factor (myc-PRF; formerly myc-PCF) is not found in cell lines representing earlier B-cell stages during which c-myc is transcribed, so it could be a negative regulator of c-myc transcription in terminally differentiated B cells. Here we report that site-directed deletion of the binding site for this protein leads to a 30-fold increase in transcription of a stably transfected c-myc fusion construct in plasmacytoma cells but has no effect in L cells or 18-81 pre-B cells, which lack the protein. Myc-PRF interacts with another widely distributed protein, myc-CF1 (common factor 1), which binds nearby, and this association may be important in myc-PRF repression.

A simple, inexpensive sterile vitreous specimen collection device with peyman vitreophage

A simple and inexpensive vitreous specimen collection device is described. This device can be connected to the Peyman Vitreophage System to obtain a sterile intraocular specimen during a pars plana virectomy.

Interaction of alpha-dansylated peptide inhibitors with porcine pepsin: detection of complex formation by fluorescence energy transfer and chromatography and evidence for a two-step binding scheme

Peptide inhibitors, specifically labeled at the alpha-amino terminus by dansylation, have been prepared by utilizing solid-phase peptide synthesis. Changes in fluorescence have been observed upon mixing these peptides with porcine pepsin that can be attributed to the formation of at least two complexes. Energy transfer between tryptophan residues of the protein and the dansyl group of the inhibitors has been detected by the unique excitation spectra generated. The kinetics of formation of the second complex can be correlated with inhibition of the catalytic activity of pepsin. Evidence for complex formation has also been obtained from gel filtration experiments using the fluorescent peptides.

Elastofibroma. A pseudotumor of myofibroblasts

The fine structure of the cell of origin in elastofibroma showed features of both fibroblasts and smooth muscle cells with fibrils that formed parallel stacks 100 A in diameter and 100 A apart and occupied large areas of the cytoplasm of some cells and an abundance of rough endoplasmic reticulum. The myofibroblast has been reported in a variety of lesions and is also present in granulation tissue and hypertrophic scars. It is postulated, in accordance with previous reports, that myofibroblasts are instrumental in the repair process and that elastofibromas are a product of constant subclinical trauma and repair.